Updated

A station wagon carrying a family of Afghan civilians struck a roadside bomb in northern Afghanistan on Sunday, killing all nine aboard, an official said.

It was the second such incident in 24 hours. The day before, six were killed when their minivan also hit a roadside bomb, this time in the southern Helmand province.

The blast in northern Baghlan province happened after midday, said Mahmood Haqmal, a spokesman for the provincial government. The vehicle had just left the local capital when it struck the buried explosive, killing six women, two men and a child.

Civilians casualties have surged in recent months as insurgents have stepped up attacks. A recent United Nations report said it documented 2,412 conflict-related civilian casualties in the first 10 months of 2010. More than three-quarters of them were caused by militant activity, a 25 percent increase from the same period in 2009, the report said. At the same time, civilian casualties attributed to pro-government forces decreased.

The dead in the Saturday's explosion in Helmand province killed both women and children, the governor's office said in a statement. It also wounded three others riding in the vehicle.

That blast occurred in Sangin district, where international forces have been taking heavy casualties while battling a strong insurgency.

In the capital, meanwhile, government officials said they are working to blunt a surge in fuel prices stemming from Iran's decision to block thousands of fuel tankers at the border — apparently out of concern that the fuel is being used by NATO forces.

The Afghan government has insisted that the fuel is for the local market only.

Commerce Minister Anwarul Haq Ahady told reporters that the government is working to increase fuel imports from other countries such as Russia, Kazakhstan and Turkmenistan. Some Afghan businesses have already struck deals with Russian companies and the Afghan government hopes that more are coming, he added.

The minister said very little progress had been made in attempts to negotiate passage for the tankers stuck at the border since late December. Between 1,800 and 1,900 of the original 3,000 stranded tankers are still waiting to cross into Afghanistan, he said.

"We are not very happy with the progress of negotiations that we had with the Iranian authorities. We have been assured many times that these tankers would be released pretty soon. They are releasing a certain number — about 40 tankers a day. Still that is not adequate," Ahady said.

He also said the Afghan government plans to tighten regulations and oversight of the fuel markets to avoid any such bottlenecks in the future.

"It has been very unpredictable, and what we want to do is replace this current system of unpredictability," he said.

Afghanistan relies entirely on imported fuel, a key commodity during winter when temperatures sink well below freezing and houses built of mud, brick or concrete offer little in the way of warmth.

Ahady said the government's efforts appear to be having some effect, noting that fuel prices have dropped from a high of about $1,500 a ton last week to about $1,350 this week.

The fuel crisis comes as NATO and Afghan forces are struggling to undermine the Taliban leadership in Afghanistan ahead of a typical uptick in attacks in the spring.

In the east, NATO said international and Afghan troops killed two insurgents and captured two suspected militants Saturday in a raid on a compound. The troops were searching for a local Taliban leader in eastern Wardak province when they shot at Saturday in Nerkh district and returned fire.

The international military coalition did not say if the targeted Taliban leader was among those killed or captured.